Upper Aptian-Albian rudist bivalves from northern Sinai, Egypt

Rudist bivalves are described from two Upper Aptian-Albian sections in northern Sinai, Egypt. Independent stratigraphical evidence is provided by orbitolinid foraminifera and sequence stratigraphic correlation with other, ammonite-bearing sections of the region. With the exception of Eoradiolites liratus (Conrad) and Sellaea, this is the first record of Lower Cretaceous rudists from Egypt. A rather continuous occurrence of rudists is recorded in the more open marine deposit at Rizan Aneiza, but they occur only in the Middle-Upper Albian at Gebel Raghawi to the south-west. In the uppermost Aptian to basal Middle Albian at Rizan Aneiza, the succession of Eoradiolites plicatus-E. murgensis-E. liratus is interpreted as a lineage of chronospecies. Of particular interest is the presence of canaliculate rudists in the Upper Albian of both sections, as there exists a large gap, spanning the Upper Aptian and most parts of the Albian, in the fossil record of the Caprininae d'Orbigny. Neocaprina raghawiensis sp. nov. and Neocaprina? sp. are recognized as ancestors of Cenomanian species of Neocaprina Plenicar and Caprinula d'Orbigny. The inclusion of these genera in the Caprininae d'Orbigny is questioned and the phylogenetic descent from an unidentified Albian taxon with well-developed myophoral cavities is suggested.